If Superman (or whoever) uses the remaining distance between you and the ground to reduce the impulse on your body. But they also have to be careful about their speed coming in to grab you, because they could easily substitute your impact with the ground for an impact with them.

See, that's how you know people here have never touched grass. Otherwise they'd know how big of a difference it makes to fall on grass vs concrete. All over a few mm of yield.

Also anecdotally I've seen videos of people catching falling children (back in the day in/r/DadReflexes). It works, empirically.